Chapter18: Population Genetics and Evolution
Evolution is the conversion of one species into one or several new species.
The subfield of genetics that deals with genetic differences within and between populations.
Factors that cause gene pool to change
Mutation
Genetic Drift
Natural Selection
Genepool
Natural Selection does not operate under the condition if all individuals of a population are identical genetically or if it is impossible to a certain condition
Multiple Selection Pressures, in many cases the loss of individials are reduced reproduction are not caused by a single factor, such as a pathogenic fungus.
Rate of Evolution: Measurement of the rate of genotype change of species and organism over a period of time
Speciation: Formation of new and distinct species in the course of evolution
Phyletic Speciation: Condition in which one species gradually becomes so changed that it must be considered a new species.
Diversion Speciation: Condition in which some population of a species evolves into a new, second species while other populations either continue relatively unchanged as the original parental or involve in a new species.
Covergent Evolution: Condition in which two distinct unrelated species occupy same or similar habitats.
The chemosynthetic hypothesis attempts to model the origin of life using only chemical and physical processes rejecting all traces of divine intervention.
- a great deal of time.
- Appropriate energy sources
- the right inorganic chemicals
Condition on earth before the origin of life
Chemicals present in the atmosphere: hydrogen sulfide (H2S), ammonia (NH3), methane (CH4)
Energy Sources : heat, radioactive decay like, uranium, radium before 4.4million years ago.